As is known in the art, rate gyroscopes have been used in a variety of applications, such as in systems for stabilization of a seeker tracking system, stabilization of various platforms, and vehicle flight control.
One type of rate gyroscope utilizes a single degree of freedom flexure component between a spinning mass and a spinning shaft. In response to an angular rate about a an axis perpendicular to the spin axis, the mass pivots about an axis of a precession. The axis of precession, the angular rate input axis and the spin axis are mutually orthogonal. It follows then that, if the flexure element that connects the rotating mass to the gyroscope shaft is a single degree of freedom flexure then the rotating mass will oscillate about its single degree of freedom if the case is subjected to an angular rate. This oscillation is a function of angular rate input.
A second type of rate gyroscope is a two degree of freedom rate gyroscope. In such a gyroscope a two degree of freedom flexure component is utilized between the spinning mass and the spinning shaft. In response to an angular rate about an axis perpendicular to the spin axis, the mass pivots about an axis of a precession. The axis of precession, the angular rate input axis and the spin axis are mutually orthogonal. It follows then that, if the flexure element that connects the rotating mass to the gyroscope shaft has two degrees of freedom then the rotating mass precesses and forms an angle between the rotating mass and the gyroscope case if the case is subjected to an angular rate. This angle is a function of the angular rate input.
Current state-of-the-art devices within the two degree of freedom gyroscope class utilize a spinning mass that is supported by a tuned flexure which decouples the rotating mass from the rotating shaft and gyroscope case. When the gyroscope case is subjected to angular inputs, the gyroscope case moves relative to the spinning mass. A position transducer determines the change in position of the case relative to the spinning mass. The position transducer and associated electronics produces an electrical signal that is fed to a torque coil, which is mounted on the gyroscope case. A magnet assembly located in the spinning mass produces a magnetic field that interacts with the current flowing in the torque coil. This interaction produces a force that restores the spinning mass to a null position. The torque coil current provides a measurement of the input angular rate to the gyroscope case.
The primary disadvantage of the current-state-of-the-art of one and two degree of freedom flexures under high dynamic load conditions is the typical use of stiff suspension beams in three of the orthogonal linear axes and two (in the case of a single degree of freedom flexure) or one (in the case of a two degree of freedom flexure) of the three angular orthogonal axes, which when subjected to high shock or acceleration, buckle under the increased load. In the case of the single degree of freedom rate gyroscope there is typically one angular axis that is a relatively weak angular spring and in the case of the two degree of freedom gyroscope there are typically two angular axes that are relatively weak.